Contactless sensor arrangement with magnetic sensor

Abstract

The invention relates to a valve (1) with a position measurement system comprising a control valve (70) for controlling a process fluid flow and a drive (60) as well as a yoke (30) for connecting the drive (60) to the valve (1), a control rod (50) which can be moved linearly within the yoke (30) and a measuring device (10) having at least one magnet-sensitive sensor (22) and at least one magnet (102), wherein the magnet (102) is fastened to the control rod (50) by means of a magnet holder (100) and the sensor (22) is fastened to the yoke (30) by means of a sensor module (20). The sensor module (20) is connected to at least one fastening means (23), (24), (40) for arranging the sensor module (20) in a yoke (30) of the control valve (70). The at least one fastening means (23), (24), (40) forms a defined interface which complements a plurality of fastening points (32) of the yoke (30). The control rod (50) has a receiving portion (54) for fixing the magnet holder (100), wherein the fastening means (23), (24), (40), the magnet holder (100) and the receiving portion (54) of the control rod (50) are designed and adapted to one another such that the sensor (22) and the magnet (100) are aligned to one another independently of a selected fastening point (32) on the yoke (50).

Description

[0001] SAMSON AG, Frankfurt / Main Non-contact sensor arrangement with magnetic sensor The invention relates to control valves for regulating process fluids with a position measuring device and to such measuring devices, in particular non-contact sensor assemblies. Control valves usually have a valve element which regulates a flow cross-section inside a valve housing, between an inlet and an outlet. The valve element is connected to an actuating stem and is usually moved by a pneumatic actuator. The actuator is usually located outside the valve housing. The actuating stem is sealingly led out of the valve housing. The invention further relates to a position measuring device for determining the position of a valve stem of an actuating element for a valve. Control valves usually require position sensors to detect the position of the valve element so that the positioner can adjust a precise position.Absolute measurement methods are preferred for this purpose, as a reference measurement is not possible in a process plant, and the valve position must be adjusted immediately for the desired opening cross-section after a malfunction or when starting up the plant. Due to the difficult environmental influences in process plants, non-contact measurement methods are preferred. Furthermore, it is preferable to install the measuring arrangement as far away from the process fluids as possible. Different valves, actuators, and positioners are usually combined, with the valve stroke ranges also varying. The actuator position is usually sensed via the actuator stem and a sensor fixed to the yoke. Magnetic or optical stroke measurement methods are particularly used as position sensors.EP 3161361 A1 and EP 1282798 B1 disclose position sensors that are located within a yoke between an actuator and a valve housing. This arrangement has the advantage that the sensor is located entirely outside the valve housing, i.e., in an area protected from the process fluid. NC-2024-1283 1 Furthermore, the position controller can be easily mounted in this area of ​​the yoke. The sensor can be connected to the position controller via a short distance. Such an arrangement is particularly suitable for a modular design. Actuators with different stroke forces and stroke lengths can be combined with different control valves using the yoke. The position sensor is located inside the yoke.A disadvantage of existing systems is that the sensors reduce the maximum possible stroke lengths of the actuators, and retrofitting existing valves with improved sensors requires a high level of adjustment effort. On the other hand, existing systems offer little flexibility for changing the position of the sensors on the valve. The object of the invention is therefore to improve the state of the art and to provide a position sensor for control valves that is suitable for different, particularly long, stroke lengths and that can be fixed in a modular manner with reduced adjustment effort and at different positions on the control valve. This object is achieved by the devices according to the independent claims. Advantageous further developments are the subject of the dependent claims.In a preferred embodiment, a position sensor comprises a sensor module with a sensor for detecting the position of a magnet relative to the sensor, a housing, and a fastening means for fastening the sensor module to the housing. The housing, in turn, has a central region for receiving a movable component, in particular an actuating rod of a valve. In particular, the housing surrounds a central region. The housing is essentially a cuboid, with the central region representing an axis of the cuboid, which runs perpendicularly and centered on two opposite sides of the housing. In an installed form of the position sensor, the actuating rod of a control valve preferably runs parallel or concentrically to the central region. As described later, the housing can be designed, in particular, as a yoke of a control valve, which is used to connect an actuator and a valve housing.The fastening means has a first fastening interface. The housing has at least one, preferably a plurality of second fastening interfaces. The second fastening interfaces are designed to be complementary to the first fastening interface, such that the first fastening interface and the second fastening interface can be connected to one another. When the first and a second fastening interface are connected, the relative position, in particular the distance and the inclination, of the sensor module to the central region of the housing is the same, regardless of which second fastening interface the sensor module is fastened to. This means that the sensor module can basically be fastened to all sides of the housing by means of the first fastening interface, and the position.

[0002] NC-2024-1283 2 of the sensor module to the central area in which the valve control rod is provided during use, on which in turn a magnet is provided for position determination, is always the same. The fastening means itself can be implemented in different ways. On the one hand, the fastening means can be an integral part of the sensor housing. On the other hand, the fastening means can be a separate component such as a plate, or the fastening means is part of another peripheral component, for example a wall of a positioner of a control valve. For all designs, it is relevant that the magnetic sensor or the sensor module is connected to a fastening means in such a way that the sensor, in an assembled state, is arranged close to a magnet for detecting the magnetic field. In this way, the definition of the interfaces can reduce the adjustment effort required to position the sensor module.In addition, it is possible for the sensor module to be arranged in different positions, for example on a yoke of a control valve. This in turn increases flexibility, particularly when retrofitting a valve with such a sensor arrangement. In at least one embodiment, the fastening means of the position sensor has a plate that closes the housing on one side. It is also conceivable for the sensor or the sensor module to be connected to a fastening or intermediate plate. In this way, the housing, for example the yoke of a control valve, can be closed by attaching the sensor module on the attachment side. As mentioned, the fastening means can, for example, be a separate plate provided with bores and / or threads that represent the interface for connection to the housing.The plate can, for example, be a plate that is arranged for fastening between a valve yoke and a positioner. This can enable the position sensor to be retrofitted without having to change any existing components. In this way, the design of a positioner, for example, can preferably remain unchanged. Only fastening options must be created on the positioner and / or the housing or yoke for attaching the intermediate plate. In particular, the intermediate plate can be a plate that is already commonly used for attaching the positioner. This plate can be reused by modifying or adding fastening holes and ensuring they are positioned precisely according to the interface to be defined. In this way, the sensor used can be converted in a material-saving manner. Alternatively, the fastening means can be a side panel of a positioner.Positioners are often located in close proximity to the valves to be controlled and are often directly connected to the yoke of a control valve. By using one of the positioner's walls as a support for the sensor, the number of components is reduced and existing mounting hardware can be reused.

[0003] NC-2024-1283 3 In this case, the interface for fastening is defined by highly precise positioning of holes and / or threads in the wall of the positioner. One embodiment of such a measuring device is designed for a control valve, wherein the control valve is constructed with an actuator, an actuating rod, and a yoke projecting around the actuating rod for connecting the valve to the actuator. The measuring device has at least one magnetically sensitive sensor and at least one magnet, as well as a magnet holder for receiving the at least one magnet. The magnet holder further has a receiving opening for receiving an actuating rod of a control valve. The sensor is provided in a sensor module. The sensor module is designed such that it is suitable for direct or indirect attachment to a positioner and / or a yoke of the control valve, and projects into the yoke when attached.The sensor module is also designed or connected to a fastening means such that, when fastened, the fastening means closes the yoke on the side equipped with the sensor module. The principle behind such magnet-sensitive sensor systems is that the electrical resistance changes when the sensor element is exposed to a magnetic field. Therefore, if the valve's actuating rod, to which the magnet is attached, is adjusted relative to the sensor, the magnetic field induced in the sensor changes, allowing the sensor module to detect the valve position without contact and adjust it accordingly. A valve with a position-measuring system according to one embodiment comprises a control valve for regulating a process fluid flow and a drive, as well as a yoke for connecting the drive to the valve, a control rod, also referred to as a control shaft, which is linearly movable within the yoke, and a measuring device.The measuring device comprises at least one magnetically sensitive sensor and at least one magnet. The magnet is attached to the control rod by means of a magnet holder, and the sensor is attached to the yoke by means of a sensor module, as described in more detail later. The sensor module is coupled to at least one fastening means designed to arrange the sensor module in a yoke of the control valve. The at least one fastening means forms a defined interface that can be complementary to a plurality of fastening points on the yoke, so that the sensor module can be arranged at different locations in the yoke without loss of functionality.In some embodiments, a plurality of fastening points can also be formed on the yoke as a defined interface, all of which are designed and provided for arranging the sensor module in such a way that the sensor module is aligned with the magnet arrangement after assembly and are functionally connected to one another. This makes it possible for the user to have flexibility in arranging the measuring device. It is understood that this interface is only formed for those fastening points that are actually intended or designed to receive or arrange the sensor module. An aligned arrangement of the sensor module and the magnets is then possible regardless of a selected fastening point intended for receiving.

[0004] NC-2024-1283 4 In the simplest form, exactly one fastening point on the yoke is designed to accommodate the sensor module. The actuating rod of the control valve has a receiving section, preferably a recess in the surface of the actuating rod, for fixing the magnet holder. The fastening means, the magnet holder and the receiving section of the actuating rod are designed and coordinated with one another in such a way that the sensor and the magnet are aligned relative to one another at each of the provided fastening points on the yoke. Due to the defined interface, the function of the sensor is therefore independent of the fastening point of the sensor module with the fastening means on the yoke selected in the individual case. The magnet holder is fixed to the actuating shaft or actuating rod. The fixation is achieved, for example, by means of the recess, specifically a groove, on the actuating shaft, so that the magnet position is coordinated with the sensor position.In this context, "aligned" means that a mounted sensor module has a position relative to the yoke and the actuating rod that corresponds to a magnet attached to a predefined position on the actuating rod. Specifically, this means that a magnet arranged at the predefined position on the actuating rod has no lateral offset, within tolerances, transverse to the main extension direction of the actuating rod relative to the sensor, but can be brought into alignment with the sensor by simple rotation around the actuating rod. In at least one embodiment, the magnet-sensitive sensor is a TMR sensor, or tunnel magnetoresistive sensor. TMR sensors have very low power consumption and high magnetic field sensitivity.Due to the high sensitivity of TMR technology, the measuring range can be increased for the same magnet length compared to other sensor types, such as a Hall effect sensor or an AMR sensor, or anisotropic magneto-resistance sensor. Thanks to the TMR effect, a 360-degree magnetic vector rotation can be clearly detected, allowing a significantly longer measuring length to be achieved for the same magnet length instead of the usual 180-degree rotation with conventional AMR technologies. This is particularly advantageous when setting up an absolute value measuring system. TMR sensors can thus help measure longer stroke lengths without having to change the size or length of the magnet. In this way, the measurable stroke length can be shifted, at which point a conventional, more complex incremental or vernier-based, 2- or multi-track measuring system would have to be used.This can enable improved use of installation space, particularly when using short control rods and / or yokes with a low overall height. In at least one embodiment of the valve, the fastening means is a wall of a positioner. Alternatively, the fastening means can be designed as an intermediate plate. Advantageously, the fastening means can be mounted directly on the yoke.

[0005] NC-2024-1283 5 Using such an intermediate plate, the sensor module can be attached to different positioners on the one hand, and to different yoke designs on the other. The intermediate plate can thus serve as an adapter for different configurations of positioners and control valve designs. The intermediate plate is also suitable for being arranged independently of the positioner for fixing the sensor module at other defined positions on the yoke. In some yoke designs, the intermediate plate is already present to provide conventional positioner attachments for a mechanical stroke pickup of the actuating rod. Such existing systems can therefore be adapted for use with the magnetic sensor system described herein through slight modification.The fastening means, in particular the intermediate plate and / or the wall of the positioner, and / or another closing plate used to close the yoke, can comprise a magnetically shielding material. Thus, the yoke can be closed and magnetically shielded using the fastening components that are already required. This closure or shielding can be achieved on multiple sides using fastening means, in particular the intermediate plate and / or wall of the positioner, and / or the closing plate. The shape of the yoke is often rectangular, with two sides of the yoke open and the remaining sides enclosed by material. Materials with ferritic components are usually used to enclose the interior of the yoke.For example, if one of the open yoke sides is closed off by a positioner and the other open side of the yoke is closed off by a sensor module with an intermediate plate, the sensor module arranged in the yoke and the magnet mounted on the actuating rod can be completely enclosed by a ferritic sleeve and thus largely or completely shielded from external magnetic fields. This can improve the measuring accuracy or measuring sensitivity of the sensor. In designs in which the sensor module is mounted on a wall of the positioner and thus the yoke is only equipped on one side, an additional closing plate can close the still open yoke part. In at least one advantageous development, the sensor module can have a plug connection for directly contacting the magnetic sensor with the positioner.In designs where the sensor module is connected directly to the positioner without the intermediate plate, a direct electrical connection can be established between the sensor module and the positioner. This eliminates the need for cable routing.

[0006] NC-2024-1283 6 The actual valve elements of such control valves usually consist of a valve housing and an axially movable valve cone mounted within the valve housing for regulating a process fluid. The valve cone can be moved by a pneumatic actuator via a valve rod. The valve rod of the valve element is sealingly guided out from the interior of the valve housing at the cover of the valve housing. The actuator has an actuator rod, previously referred to herein as the control rod. The actuator rod and the valve rod can be connected within the yoke by means of a coupling. Alternatively, as chosen here for the sake of simplicity of description, only one rod, namely the control rod, can be used, which is then coupled directly to the valve cone. The valve cone is exposed to high process pressures during operation. With asymmetrical cone geometries, this can lead to a torque on the actuator rod.The actuator stem, for example of a pneumatic diaphragm actuator, is fixed to a plate of the diaphragm, and the diaphragm itself is attached to the actuator housing, so that any rotation of the actuator stem depends on the elasticity of the free length of the diaphragm. This rotation influences the measuring accuracy of the position measuring system, since the magnet can rotate by up to 5° relative to the magnetic sensor during operation. It is therefore a further object to provide a measuring device for a control valve, and in particular a magnet holder and a valve, with increased tolerance to rotation of the magnet relative to a magnetic sensor. A magnet holder suitable for such a control valve according to one embodiment for attachment to a control rod of a control valve has a holder with a bearing section and two legs.The support section can be geometrically based on the shape of a half-cylinder, with concentrically arranged outer and inner surfaces. The inner surface has a radius of curvature that corresponds to the radius of curvature of a control rod to be accommodated. The legs of the holder extend radially from the support section and are formed opposite one another. The legs span an opening of a predefined size. This opening and the inner contours of the support section are dimensioned such that the magnet holder can accommodate a control rod of a valve. The shape of the magnet holder formed in this way can, in particular, resemble the shape of a horseshoe. The magnet holder also has a fixing element on its inner contour. This fixing element can improve the hold of the magnet holder on the control rod.On an outer side, the magnet holder has at least one magnet, preferably two magnets arranged side by side in a row, as seen in the circumferential direction of the magnet holder. This allows the magnet(s) to be positioned close to a magnetic sensor. A magnet receptacle can be provided for the magnet(s). The magnets can also be integrated into the holder, for example, cast in the material of the magnet holder during the manufacturing process.

[0007] NC-2024-1283 7 It is particularly advantageous if two or more magnets are arranged next to one another, in particular parallel to one another, along a circumferential direction of the magnet holder arranged around a control rod. It has been shown that this arrangement on the magnet holder results in favorable magnetic field lines, so that rotation of the shaft and the magnet holder has almost no influence on the measurement signal. In this way, the tolerance of the sensor system with regard to rotation of the magnet holder relative to the sensor during operation can be increased. In summary, the magnet holder is open on one side so that it can be subsequently attached to the control rod after complete assembly of the control valve, consisting of an actuator, a yoke, a valve and a control rod. A recess, for example in the form of a groove as a receiving section on the control rod orAn elevation, for example in the form of a projection as a fixing element, as well as a complementary shape of the fixing element on the magnet holder allow improved, preferably exact, axial positioning of the magnet holder on the actuating rod and thus of the magnet system relative to the magnetic sensor. It goes without saying that the projection can also be formed on the actuating rod and the groove can also be formed on the magnet holder. All components have dimensions that lie within a defined dimensional accuracy and tolerance. In this way, it can be ensured that, after assembly, the distance between the magnet system and the magnetic sensor lies within the permissible tolerance range for the required measurement accuracy. By using a magnetic sensor and such a magnet holder, a measuring device is created that can be both electrically and mechanically contactless and wear-free.In this way, a measuring device for a control valve can be provided, wherein the measuring device has at least one magnetically sensitive sensor and at least one magnet, as well as a magnet holder for receiving the at least one magnet. The magnet holder further has a receiving opening for receiving an actuating rod of a control valve. The sensor is provided in a sensor module, which can be arranged in the yoke and, at least indirectly, fastened to the yoke. The magnet holder has a self-adjusting adjusting element. This preferably has at least one inclined surface, which is designed to fit with a predefined receiving section, in particular on an actuating rod of a control valve, and which, in an assembled state, engages or can be brought into engagement with this receiving section. At least one opening for receiving at least one clamping screw is formed in the adjusting element.The magnet holder can be clamped to the actuator rod using at least one screw for attachment. This is particularly advantageous because the angular position of the magnet holder can be adjusted to the exact position of the magnetic sensor before clamping it to the actuator rod.

[0008] NC-2024-1283 8 particularly advantageous because the control rod is rotationally symmetrical and the actual angular position of the control rod in the valve can only be determined after the control valve has been fully assembled. In at least one embodiment, the magnet holder is fixed by means of a clamping screw arranged transversely through the two legs of the magnet holder. This has the advantage that a high clamping force can be generated and the clamping screw does not come into direct contact with the control rod. In comparison to embodiments in which the recess of the clamping screw acts directly on the control rod, the control rod, in particular the recess, i.e. the receiving section or the groove, is not damaged with a transversely running screw.When using plastic for the magnet holder, it can also be advantageous to use a clamping screw that is not supported on the leg, since otherwise, expansion of the legs of the magnet holder cannot be ruled out and the clamping force on the actuating rod can decrease over time. Thus, the use of such a transverse clamping screw can improve the maintenance of the clamping force. If the clamping screw runs through both legs, with the legs being pulled towards each other by a corresponding clamping screw, a clamping force can be exerted on the actuating rod that will remain largely unchanged over time. In one embodiment of a valve with a position measuring system, a control valve for regulating a process fluid flow has an actuator and a yoke for connecting the actuator to the valve, an actuating rod that is linearly movable within the yoke, and a measuring device.The measuring device has at least one magnetically sensitive sensor and at least one magnet, wherein the magnet is arranged on the actuating rod by means of a magnet holder, and the sensor is arranged in the yoke by means of a sensor module and is fastened, at least indirectly, to the yoke. The magnet holder, in turn, has an adjusting element which is complementary in shape to a receiving section on the actuating rod, such that a magnet holder, which is arranged on the actuating rod by means of the adjusting element and receiving section, is axially fixed and the magnetic sensor and the magnet are arranged in alignment with one another. The magnet holder further has two opposing legs which span an opening width corresponding to the actuating rod diameter, so that the actuating rod can be inserted radially into the magnet holder or, in an assembled state, is inserted through the opening.This allows a control valve to be equipped with a non-contact and wear-free measuring system. In particular, a valve can be retrofitted with such a measuring device without having to disassemble the valve assembly.

[0009] NC-2024-1283 9 In at least one embodiment of the valve, at least two magnets arranged next to one another, in particular arranged parallel to one another, are fixed to the magnet holder. This can contribute to a higher tolerance in the event of a possibly rotated arrangement of the magnets during initial assembly or in the event of rotation of the actuating rod during operation. The magnet(s) can be designed as bar magnets. The length and dimensions of the magnets can be easily adapted to different drive strokes. In addition, different actuating rod diameters can be easily realized, for example by using a differently dimensioned magnet holder, for example with a larger or smaller diameter. In at least one embodiment, a valve with a position measuring system has a magnet holder which is fixed to the actuating rod by means of a clamping screw.This can improve the hold of the magnet holder and reduce unintentional twisting of the magnet holder on the actuating rod. In alternative designs, the valve has a magnet holder in which a clamping screw is arranged transversely through the two legs of the magnet holder and fixes the magnet holder by pulling the legs towards each other. The clamping screw can advantageously also be designed as a fitting screw and fix the magnet holder radially to the actuating rod. This can reduce play of the magnet holder on the actuating rod and thus allow for improved measuring accuracy of the sensor. The fitting screw can be designed such that it also forms a positive connection with the valve rod groove. Such a positive assembly can further reduce axial slippage.Advantageously, the magnet holder of a valve with a position measuring system can have at least one locking lug for radial fixation on the actuating rod on an inner circumference in which the actuating rod is accommodated. In this way, the magnet holder can be arranged at the designated location on the actuating rod and secured against accidental removal of the magnet holder from the rod by engaging the locking lug. The locking lugs also serve for rough pre-adjustment. Once the magnet holder has engaged, it can no longer slip in the radial direction. The magnet holder can comprise a plastic or be made of a plastic. In particular, the magnet holder can be made of PEEK and can be thermoplastically or mechanically manufactured.

[0010] NC-2024-1283 10 A control valve with a position measuring system can also have a magnet holder which has a non-magnetically conductive metal or is made from it. This can be a magnet holder produced using an MIM process, for example. In this way, disturbances in the magnetic field of the magnets during measurement can be reduced. Embodiments, developments and examples of the invention are explained in more detail below with reference to the attached drawings. The figures show: Fig. 1 a sensor module and a magnet holder; Fig. 2 a perspective view of an embodiment of a measuring device in a disassembled state; Fig. 3 a perspective view of the measuring device according to Fig. 2 in the assembled state; Fig. 4 a sectional view of a control valve with a measuring device according to one embodiment Fig. 5 a sectional view of a control valve with a measuring device according to a further embodiment Fig.6 shows a sectional view of a control valve with a measuring device according to a further embodiment. Fig. 7 shows a perspective view of the magnet holder according to an embodiment. Fig. 8 shows a perspective view of a magnet holder according to a further embodiment. Fig. 9 shows a perspective view of the magnet holder from Fig. 8 in the assembled state. In the figures, the same reference numerals designate the same or similarly acting components. For reasons of clarity and better readability, the description of such components is only repeated where necessary. Fig. 1 shows an embodiment of a sensor module 20 and a magnet holder 100 for a control valve. The sensor module 20 has a sensor housing 21. The basic structure of the sensor housing 21 forms a cuboid which has two projections 23 on one side, hereinafter also referred to as the fastening side, which have two openings 26 for fastening.The openings 26 are provided as holes that allow the sensor module 20 to be attached to a fastening means. In the embodiment shown, the fastening means is an intermediate plate 24, as described in further detail later. In alternative embodiments discussed later, the fastening means is designed as a wall 41 of a position controller 40.

[0011] NC-2024-1283 11 The projections 23 therefore represent a fastening means for the sensor module (20) in this and other embodiments. The projections can, in particular, also be flat, so that an intermediate plate 24 or the use of a position controller 40 as a module carrier can be dispensed with. On a side of the sensor housing 21 that faces away from the fastening side, a recess is formed in the sensor housing 21. The sensor 22, designed as a magnetic sensor, is arranged on an inner wall of the recess at the distal end of the sensor housing 21, starting from the fastening side. The magnetic sensor is fastened to a circuit board 27, which is connected to the sensor housing 21. The magnetic sensor or the circuit board can be fastened to the sensor housing 21 by screwing, as shown in Fig. 1. In this way, it is possible to precisely define the position of the fastening holes.Likewise, in the embodiment shown, the sensor housing 21 is attached to the fastening means 24 by screws. The sensor module 20 has a cable feedthrough (not shown here) or, alternatively, a connector for contacting external components, such as a position controller. The intermediate plate 24 is formed with a plurality of through-holes 25. The position of the through-holes 25 is precisely predefined. The through-holes 25 allow the intermediate plate 24 to be attached to other components, such as a housing of a position controller 40 or a housing or yoke 30 of a valve, as will also be described in further detail later.In addition, the intermediate plate 24 has a plurality of fastening holes 28, here two, which are designed to fasten the intermediate plate 24, for example, to a valve yoke or generally to a housing. Fig. 1 further shows a magnet holder 100. The magnet holder 100 is arranged on an actuating rod 50. For this purpose, the magnet holder 100 has a holder 101. The holder 101 has an opening which essentially corresponds to the circumference of the actuating rod 50, around which the magnet holder 100 is provided to be arranged. In the embodiment shown, the magnet holder 100 has an adjusting web 104 along a surface of the inside of the holder. The adjusting web 104 is designed to engage with a groove 54 which is formed at a predefined position along the surface of the actuating rod 50. Preferably, the adjusting web 104 is designed such that it has a positive connection to the groove 54.When the magnet holder 100 is mounted on an actuating rod 50, for example, of a valve 1, at least one magnet 102—two magnets 102 in the embodiment shown in Fig. 1—is arranged on a side facing the sensor module. The magnets 102 are arranged in the circumferential direction and, in the embodiment shown, parallel to one another. Furthermore, the magnet holder 100 is provided on the actuating rod in such a way that the magnets 102 are directed toward the sensor housing 21 and specifically toward the magnetic sensor.

[0012] NC-2024-1283 12 are aligned. In the context of the embodiment according to Fig. 1, “alignment” means that the magnets arranged on an actuating rod move past the magnetic sensor at a minimum possible distance within tolerances when the actuating rod is moved vertically, as occurs when a valve is adjusted by a valve actuator, and are therefore not rotated or offset relative to the position sensor along the actuating rod 50. The magnet holder 100 also has a clamping screw 106. The clamping screw 106 is arranged on a side of the actuating rod opposite the magnets 102. The clamping screw allows the adjusting web 104 to be clamped in the groove 54. In alternative embodiments, the clamping screw 106 can also be replaced by a different fastening method, or even omitted entirely. The actuating rod 50 has a drive connection 56 at a first end for connecting the actuating rod to a valve actuator.At an opposite end of the control rod, it has a valve connection 52 for connection to the valve element controlling the process fluid. The valve connection of the control rod can also be a connection to a valve rod, wherein the valve rod is guided into a valve housing and coupled therein to the actual valve element. Fig. 2 shows a perspective view of a measuring device 10 for a control valve. The components already described in connection with Fig. 1 are also provided, even if they are concealed by other components and therefore not visible. Fig. 2 also shows a sensor module 20. The sensor module 20 is in turn fastened to an intermediate plate 24. A valve drive 60 is arranged on the drive connection 56 of the control rod 50 (not visible in Fig. 2). A housing, also referred to as a yoke in the context of valves, is formed around the control rod 50 and on the valve drive 60.The housing is essentially cuboid-shaped. The valve drive 60 is arranged on the top side of the housing. The valve rod protrudes centrally through the center of the housing 30, concentric with the surface normal of the top and bottom of the housing. On the underside of the housing, a cover plate 35 is formed, through which the actuating rod 50 protrudes from the housing. According to the embodiment shown in Fig. 2, two opposing lateral surfaces of the housing are closed with housing plates 36, which are formed with openings according to the intended functions. The number and type of openings can vary depending on the function. A plurality of mounting holes are formed on the housing for attaching the plates. The exact position of the mounting holes on the housing is again precisely predefined. As indicated in Fig. 2 and shown in Fig.3, the intermediate plate 24 serves both to accommodate the sensor module 20 and to attach it to it.

[0013] NC-2024-1283 13 positioner 40 as well as the attachment to the housing. Previously known attachment plates in devices from the prior art serve to attach conventional positioners, which are already designed, for example, for connection to a valve yoke, and can be easily modified or reused for use with a magnetic sensor. The intermediate plate 24 closes off one of the open sides of the housing. Thus, in this embodiment, one side of the housing is open. As previously described, the plates closing the housing can have properties for shielding magnetic fields. Thus, with the appropriate choice of material, magnetic shielding of five of the six housing sides can be achieved using the embodiment shown in Fig. 2 or Fig. 3 with the commonly used components. It goes without saying that the remaining open side can also be closed with a plate.This enables complete magnetic shielding. A position controller 40 is provided on a surface of the intermediate plate 24 facing away from the sensor housing 21. The wall of the position controller facing the intermediate plate 24 has a plurality of through-holes 42, of which only one is visible due to the representation in the figure. The through-hole 42(s) of the position controller 40 is / are congruent with the through-holes 25 provided in the intermediate plate 24 in an assembled state. Fig. 3 shows the measuring device according to Fig. 2 in the assembled state from a slightly different perspective. The position controller and intermediate plate are connected by screws which are screwed through the through-holes 42 of the position controller and the through-holes 25 of the intermediate plate (not visible in Fig. 3).The positioner 40 has a screw channel 43 to access the through holes 42. The through holes and / or the through holes 25 can also have a thread. In this way, the play with which the components are fastened to one another can be minimized. Fig. 4 shows a cross-sectional view of a control valve with a measuring device. Fig. 4 shows an embodiment of the measuring device as shown in Figs. 2 and 3. In addition, the control rod 50 is connected to a valve housing 70 on the valve connection side or is coupled to the actual valve element that regulates the process fluids. The positioner 40 is coupled to the sensor module 20 and the valve yoke, previously also referred to as the housing, via the intermediate plate 24. Starting from the valve housing 70, the control rod 50 runs through the central region of the yoke 30 to the valve actuator 60.A side of the yoke 30 opposite the positioner 40 is closed with a closure plate 34. The fastening of the positioner 40 or the intermediate plate 24 and the closure plate 34 to the yoke 30 cannot be seen in the figure due to the selected sectional plane.

[0014] NC-2024-1283 14 As described in the context of Fig. 1, the actuating rod 50 in the preferred embodiment shown here has a groove 54. The groove 54 is formed at a predefined position on the actuating rod, at which position a magnet holder 100 is arranged. The magnets 102 are arranged on a side of the actuating rod 50 facing the sensor module. The position of the magnet holder 100 or of the magnets 102 held by the magnet holder 100 can be precisely predefined by using such a groove 54 and thus can take place without calibration of the sensor measurement, or can allow an essentially adjustment-free absolute measurement. As previously described, this allows the precise positioning of the sensor module relative to the magnet holder or relative to the magnets. Fig. 5 shows an alternative embodiment of a control valve with a position measuring device. The sensor module 20 is attached directly to the side wall 41 of the position controller 40.In this embodiment, the sensor module 20 has a connector 29. The connector 29 can be used for direct electrical coupling to the position controller 40. For this purpose, the position controller 40 in turn has a connector 44. The connectors 29 on the sensor housing 21 and the connector 44 on the position controller 40 are aligned and are automatically coupled and connected when the sensor housing 21 is attached to the position controller 40. In alternative embodiments, such as those shown in Fig. 4 or Fig. 6, the sensor module 20 can have a cable guide. In this way, a connecting cable can be guided from the sensor module 20 to the position controller 40. This cable guide can, in particular, also run through the interior of the yoke 30. Fig. 6 shows a further embodiment of a control valve with a position measuring device. The sensor module 20 is arranged on a mounting plate, corresponding to the intermediate plate 24.The fastening plate is therefore provided with the same reference numeral 24, in particular because it can explicitly be the same plate, which also enables fastening between yoke 30 and positioner 40. The fastening plate 24 is arranged on a side of the yoke 30 facing away from or opposite the positioner 40, as shown in Fig. 6. As previously mentioned, a cable outlet is optionally provided on the sensor module 20, which is not shown in Fig. 6. This makes it possible to fasten the sensor module 20 in a position facing away from the positioner 40 and to contact it with the positioner 40. Valves and associated components such as actuators, yokes or positioners are generally highly standardized due to the associated development costs. The individual components of the sensor module 20, including the intermediate orMounting plate 24, as well as the holes in the wall 41 of the positioner, therefore also have standardized dimensions with regard to their mountings.

[0015] NC-2024-1283 15 For this reason, it is possible to precisely define the position of attached components. This allows a mounting interface to be defined if the position of the necessary fastening elements, for example, the through holes 25 or mounting holes 28 of the intermediate plate 24, the through holes 42 of the positioner 40, or the mounting holes of the housing, is known. Through a suitable design of the sensor housing 21, the magnetic sensor can thus be arranged at a precisely predefined position. Likewise, the dimensions of the actuating rod 50 and the position of the groove 54, as previously mentioned, are also standardized or precisely known, so that the magnet holder 100 is positioned at a precisely specified position on the actuating rod 50 and relative to the magnetic sensor.Thus, only a rotation of the magnets 102 around the longitudinal axis of the actuating rod, which is held by the magnet holder 100, can occur after installation of the magnet holder 100. Compensation for the position of the magnets rotated in this way can be easily achieved during installation. For this purpose, for example, a mark applied to the magnet holder 100 and / or the sensor housing can be aligned with one another or relative to one another, or another tool for measuring the alignment of the magnets can be used. The position of the magnet holder 100 adjusted after assembly is fixed in the embodiments shown in Fig. 4, Fig. 5 and Fig. 6 by means of the clamping screw 106. Fig. 7 shows a magnet holder corresponding to the embodiment in Fig. 1 in an enlarged, perspective view without the actuating rod.The holder 101 of the magnet holder 100 has a substantially horseshoe shape, with a semicircular bearing section 103, which is provided for positioning directly in an adjusting rod, and two legs 105 extending tangentially from the bearing section 103. The clamping screw 106 is designed such that it projects into a threaded bore through one of the legs 105 into or through the holder 101. When used with an adjusting rod, rotating the clamping screw 106 forces the screw shaft against the adjusting rod, resulting in a clamping and thus a secure fit of the magnet holder 100. The adjusting web 104 is formed in the magnet holder 100 along an inner contour of the holder 101. In particular, the adjusting web has a wedge or prism shape, the width and flank shape of which enable a positive fit with the groove provided in the adjusting rod.The magnets 102 are arranged at a position opposite the clamping screw 106. In the embodiment shown in Fig. 7, the magnets 102 are partially enclosed by the material of the magnet holder 100. In alternative embodiments, the magnets 102 can be provided as an integral component in the magnet holder 100, i.e., completely enclosed by the holding material. Magnetization of the magnets can occur before or after the magnets are installed in the magnet holder. Fig. 8 shows a further embodiment of a magnet holder 110. The magnet holder 110 according to Fig. 8 differs essentially from the magnet holder 100 shown in Fig. 7 in that, instead of a clamping screw, which is intended to come into direct contact with the actuating rod, a clamp is used.

[0016] NC-2024-1283 16 is provided, which does not have a screw but rather the legs of the holder 101 itself as the clamping element. For this purpose, a through-hole is formed through one of the legs 105 of the holder 101 as a screw receptacle 112 for a head portion of a clamping screw, and a threaded hole 114 is formed in the other leg for receiving a threaded end of a screw and for screwing the screw into the threaded hole 114. The screw receptacle 112 and the threaded hole 114 are arranged in the fixing element or run through the fixing element. A center point of the through-opening of the screw receptacle 112 is further away from a free end of the leg 105 than the center point of the threaded hole 114. This results, as can be seen in Fig. 9, in an inserted screw running obliquely from one leg to the other. It is understood that this is only one possible embodiment.The screw can also have a straight line without deviating from the spirit of the invention. Furthermore, it is possible to replace the threaded hole with a through-hole and to use another type of screw fastening, for example, using a nut or a bolt lock. As previously described, the holder 101 is essentially a half-cylinder whose open ends merge into the legs 105. A locking lug 118 is provided in the area of ​​the transition from the curved support section 103 to the legs 105. The locking lug is a projection on the inner contour of the magnet holder, which is dimensioned and designed such that an adjusting rod with a defined diameter can pass past the locking lug when the adjusting rod is inserted into the magnet holder by elastically pushing the legs 105 apart. However, due to the restoring force of the legs, the locking lug fixes the adjusting rod in the holder 101.As a result, the position of the adjusting rod is already roughly adjusted and only the alignment of the magnets 102 needs to be carried out during assembly. A sensor would ideally be arranged along axis A in Fig. 9 in order to detect the most symmetrical course of the magnetic field lines and the strongest possible magnetic field in the sensor. Fig. 9 further shows a clamping screw 116, which in this case is designed as a fitting screw engaging in the groove 54 - not visible in Fig. 9. The clamping screw 116 has a tangential course to the adjusting rod 50 received in the magnet holder 100. During use, the adjusting rod 50, in particular the groove 54 of the adjusting rod 50, is brought into engagement with the adjusting web 104 of the magnet holder 100 through the opening of the legs 105 in the magnet holder 100.

[0017] NC-2024-1283 17 LIST OF REFERENCE SYMBOLS 1 Valve 10 Measuring device for control valve 20 Sensor module 21 Sensor housing 22 Sensor 23 Projection 24 Intermediate plate 25 Through hole 26 Opening 27 Circuit board 28 Mounting hole 29 Connector 30 Yoke 32 Mounting hole 34 Cover plate 35 End plate 36 Side plate 40 Positioner 41 Positioner wall 42 Through hole 43 Screw channel 44 Connector 50 Actuating rod 52 Valve connection 54 Groove 56 Actuator connection 60 Valve actuator

[0018] NC-2024-1283 18 70 Valve housing 100 Magnet holder 101 Bracket 102 Magnet 103 Support section 104 Adjustment bar 105 Leg 106 Clamping screw 112 Screw receptacle 114 Threaded hole 116 Clamping screw 118 Locking lug

[0019] NC-2024-1283 19

Claims

PATENT CLAIMS 1. Valve (1) with a position measuring system comprising a control valve (70) for regulating a process fluid flow and a drive as well as a yoke (30) for connecting the drive to the valve (1), a control rod (50) that is linearly movable within the yoke (30), and a measuring device (10) having at least one magnetically sensitive sensor (22) and at least one magnet (102), wherein the magnet (102) is fastened to the control rod (50) by means of a magnet holder (100) and the sensor (22) is fastened to the yoke (30) by means of a sensor module (20), characterized in that the sensor module (20) is connected to at least one fastening means for arranging the sensor module (20) in a yoke (30) of the control valve (70), wherein the at least one fastening means forms a defined interface,which is complementary to a plurality of fastening points of the yoke (30), and wherein the actuating rod (50) has a receiving section for fixing the magnet holder (100), wherein the fastening means, the magnet holder (100), and the receiving section of the actuating rod (50) are designed and coordinated with one another such that the sensor (22) and the magnet (102) are aligned relative to one another, regardless of a selected fastening point on the yoke (30) provided for receiving.

2. Valve (1) with a position measuring system according to claim 1, characterized in that the magnet-sensitive sensor (22) is a TMR sensor.

3. Valve (1) with a position measuring system according to one of the preceding claims, characterized in that the fastening means is a wall of a position controller (40).

4. Valve (1) with a position measuring system according to one of claims 1 to 2, characterized inthat the fastening means is an intermediate plate (24).

5. Valve (1) with a position measuring system according to one of the preceding claims, characterized in that the fastening means can be mounted on the yoke (30).

6. Valve (1) with a position measuring system according to one of the preceding claims, characterized in that the fastening means and / or a closure plate (34) comprise a magnetically shielding material and the yoke (30) is closed on several sides by means of a fastening means and / or closure plate (34).

7. Valve (1) with a position measuring system according to one of the preceding claims, characterized in that the sensor module (20) has a plug connection for directly contacting the sensor (22) with the, NC-2024-1283 20 Position controller (40).

8. A measuring device (10) for a control valve with a drive, a control rod, and a yoke surrounding the control rod for connecting the valve to the drive, wherein the measuring device comprises a housing, at least one magnetically sensitive sensor (22), and at least one magnet (102), as well as a magnet holder (100) for receiving the at least one magnet (102). Furthermore, the magnet holder (100) has a receiving opening designed to receive a control rod (50) of a control valve (1), and the sensor (22) is provided in a sensor module (20).

9. The sensor module (20) is designed for direct or indirect attachment to a position controller (40) and / or the housing in such a way that the sensor module (20) projects into the housing when attached to the housing, and the housing is closed on the side equipped with the sensor module (20).A position sensor comprising a sensor module (20) with a sensor (22) for detecting the position of a magnet (102) relative to the sensor (22), a housing, and a fastening means for directly or indirectly fastening the sensor module (20) to the housing, wherein the housing has a central region for receiving a movable component, in particular an actuating rod (50) of a valve (1), characterized in that the fastening means has a first fastening interface and the housing has a plurality of second fastening interfaces that are complementary to the first fastening interface, such that the relative position of the sensor module (20) to the central region of the housing is the same for every second fastening interface, regardless of a selected second fastening interface of the sensor module (20).Position sensor according to claim 9, characterized in that the fastening means has a plate closing the housing on one side. NC-2024-1283 21

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